Conjoint-measurement analysis of composition rules in psychology.

Composition rules are theories that describe the relationships among several measurable variables. Conjoint measurement provides methods for analyzing such rules using ordinal information only. This analysis is applied to a class of four composition rules in three variables A + P + U, (A + P) U, AP + U, APU~, which have been widely employed in different areas of psychology. It leads to the formulation of observable ordinal properties that can be used to test and diagnose which of the rules, if any, is appropriate for a given set of data.